User Equipment (UE) devices, such as mobile telephones and tablet computers, may move or “roam” from one wireless communication network to another, such as when moving from one geographic area to another geographic area, or due to changes in wireless communication service. For example, a UE device moving from a first geographic area to a second geographic area may roam from a first wireless communication network covering the first geographic area to a second wireless communication network covering the second geographic area. As another example, a UE device may roam from a first wireless communication network to a second wireless communication network covering the same geographic area in response to degraded service from the first wireless communication network. This ability of a UE device to roam among wireless communication networks helps ensure that the UE device has quality service available as the UE device moves to different geographic areas and as wireless communication service changes in quality.
In addition, new technologies are expected to increase the number of wireless communication networks available in many areas. For example, multiple wireless communication service providers may establish respective wireless communication networks in a common area using shared radio frequency (RF) spectrum, e.g., in citizens broadband radio service (CBRS) spectrum or in unlicensed spectrum, operating according to aspects of a long-term evolution (LTE) protocol or a fifth generation (5G) New Radio-Unlicensed (NR-U) protocol. As another example, site operators may establish neutral host networks, e.g. LTE networks or 5G NR-U networks, that are open to subscribers of multiple wireless communication service providers, to improve wireless communication at their respective sites. Such increase in wireless communication networks may increase opportunities for UE devices to roam among wireless communication networks.